Joint injections are performed to help reduce inflammation and restore a horse’s performance level. There are three common substances used in joint injections.
Corticosteroids help reduce inflammation. Hyaluronic acid and polysulfated glycosaminoglycan are used to regenerate cartilage, as well as lubricate and help the joint heal. Joint injections should be used in horses with a lameness issue or arthritic changes.
The best way to determine if your horse has an issue that may require joint injections is for your veterinarian to perform a basic lameness exam including flexion tests.
Nerve blocks can be used to determine a more specific location of the lameness. Your veterinarian will do this by localizing which leg is painful and begin to block or numb nerves on that limb starting with the lowest nerves possible. After each block, the horse will be jogged and flexed until improvement is seen. This process helps localize the lameness issue. Radiographs may also be performed to look for bony changes. MRI is now available and can assess both soft tissue and bone.
Joint injections are not without risk. Joint flare can occur, which means that the joint becomes inflamed following the injections. Lameness due to joint flair can last for hours, days or weeks. The problem with this condition is that it must be differentiated from a true joint infection.
Horses will typically develop swelling, heat and severe pain in an infected joint around three days after injections. This is a serious condition and can be career-limiting. High doses of corticosteroids can cause life-threatening inflammation of the foot called laminitis.
This is more common when multiple joints are injected and with higher doses of corticosteroids. Articular cartilage degeneration, which is thinning and weakening of joint cartilage, can occur with frequent and high-dose use of corticosteroids.
With all that being said, some questions to ask yourself before you begin having your horse injected include: Does my horse really need injections? What should the joint be injected with? How much rest will my horse need? How frequently should I have my horse injected?
Horses with lameness issues due to arthritic changes in the joint are great candidates for joint injections. Most equine veterinarians recommend using a combination of corticosteroids and hyaluronic acid or polysulfated glycosaminoglycan. Horses should be rested for at least 72 hours after injections.
Every horse will respond differently to joint injections; therefore, every horse will need to be injected at different frequencies. This is a decision you and your veterinarian will make together based on lameness exam findings, radiographs, performance history and competition schedule, among other factors.